Hydration or drinking systems adapted to be worn or carried by the user typically comprise a bladder supported by a backpack or the like, a bite valve, and a hose extending from the bladder to a bite valve such that the bite valve can be arranged adjacent to the user's mouth. When thirsty, the user takes the bite valve in his or her mouth, bites to open the valve, and sucks to draw fluid, typically water, from the bladder. Such hydration systems can be used in a substantially hands-free manner.
Hydration systems can be used in both summer and in winter. A typical hydration bladder rarely freezes during winter use because it is generally kept near the body. However, under severe conditions, the drinking hose and bite valve can and do freeze, sometimes quickly, when used in the winter.